The present invention relates to liquid crystal displays (LCDs) and more particularly relates to LCD heaters and even more particularly relates to controls for LCD heaters.
In the past, LCD heater plates have been incorporated to provide a uniform temperature across the LCD surface. The heater has typically been deposited material such as indium tin oxide (ITO) applied to a glass cover placed adjacent to the liquid crystal layer within the display. Electrical current is then passed through the ITO coating across the display face to generate uniform heating.
Available temperature sensors, for providing feedback to thermal controls functions, are opaque and too large to be placed within the stacked layers comprising the display. Consequently, the thermal sensors have been placed about the periphery to provide information about the temperature of the LCD material. This method has limitations for determining the temperature of the central portion of the display and extent of thermal gradients present.
Thermal gradients form across the surface of the display due to non-uniform flow of heat from the liquid crystal material to the adjacent environment and display housing.
Consequently, there exists a need for improved thermal sensing across the LCD assembly, in order to provide better thermal management of the display.